A wireless asset sensor or alarm device can be attached to or mounted on some valuable object for its protection. The mounted sensor is generally small and unobtrusive so that its presence is not obvious. Such sensors or devices monitor the asset's movement, transmitting an alarm signal if the movement is greater than a pre-determined tolerance. Typically there are three possible conditions that cause an alarm to be triggered. A first is if the object is sensed to be in motion for more than about one second, a second is if the object is sensed to be in motion for more than about five seconds, and a third is if the object is tilted more than 30° off horizontal with reference to the Earth's gravitational field.
These asset sensors generally operate in conjunction with the control panel of a fixed or permanently installed security system in a static environment, such as a building. Each alarm condition can be associated with a loop on its associated security system control panel. Typically a control panel receives alarm signals from sensors, interprets each signal, and transmits alarm notifications in accordance with the signal. The notification may be a display on the control panel, an audible alarm, other visual notification such as flashing lights, or any combination thereof. A central office may be notified of the alarm in addition to, or instead of, local notification on the control panel.
However, there is a need for sensors with similar motion-detection functionality in non-static environments, in which the entire protected premise is subject to motion. Such premises can be boats, houseboats, RVs and other vehicles. For instance, a boat may have fishing gear or navigation electronics exposed on the deck, or removable outboard motors; it is desirable to protect these assets, and the asset sensor is an ideal choice. However, it cannot be used in these applications because the premises are not static. Instead, a moored boat, for example, will sway on the water's surface, and the swaying motion will cause false alarms. Furthermore, sensors as known in the art may cause false alarms in areas of high seismic activity, e.g. certain locations on the West Coast of the United States. Hence there is a clear need for an enhanced sensor capable of functioning even in these sorts of situations.